R Theory V3 Diffuser
#1
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From: Seattle
R Theory V3 Diffuser
RTheory just released a group buy on their new V3 Diffuser what does everyone think. Looks like it should be pretty effective paired with a underbody and front splitter.
#6
https://www.instagram.com/rtheorymotorsports/
I'm heading to the car right now. I'll take some pictures when I get there.
#7
This diffuser is the first prototype. I should mention I made some minor changes to make assembly easier and much cleaner. The production version will look the same as this version for the most part. And sorry for the messy garage picture, I'll take more if needed outside when it stops raining!
#8
Also I'll mention V3 requires a mild bumper cut. Thankfully The Car Passion Channel just uploaded a youtube video on how to do a rear bumper cut!
#11
I understand it's hard to do for several reasons but I wish places would give something like a lap time bonus or MPH increase when marketing these products. Then again I'm not sure I've ever done a cosmetic mod on one of my cars unless you count painting the wheels or fixing dents. Know your audience and all that.
Why is a curved diffuser better than one with abrupt angle changes? It appears to make sense, but I know from my 2-stroke days and building pipes, that those pipes want abrupt angle changes into the expansion chamber and not smooth or curved into the expansion chamber. I have to think that rapidly expanding air, 2-stroke pipes and aero may be quite similar?
#13
I would lower the bar even further, how about testing with flow-viz paint to show any aero benefits? Or a video driving through low area with fog? There are so many easy ways to get aero data.
Why is a curved diffuser better than one with abrupt angle changes? It appears to make sense, but I know from my 2-stroke days and building pipes, that those pipes want abrupt angle changes into the expansion chamber and not smooth or curved into the expansion chamber. I have to think that rapidly expanding air, 2-stroke pipes and aero may be quite similar?
Why is a curved diffuser better than one with abrupt angle changes? It appears to make sense, but I know from my 2-stroke days and building pipes, that those pipes want abrupt angle changes into the expansion chamber and not smooth or curved into the expansion chamber. I have to think that rapidly expanding air, 2-stroke pipes and aero may be quite similar?
#14
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iTrader: (1)
Joined: Sep 2016
Posts: 1,859
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From: Seattle
Just to get this thread back on track. The above are great links for aero. Kyle Drives has many good videos explaning aero that everyone exploring aero should watch. Race care engineering just buy the book its worth it.
I understand aero and the purpose and concept of this diffuser (I have been waiting for this release and will buy one) The intent of this threat were to discus the ascetics, shortcomings and where it excels. Its pretty obvious this is functionally better than the v1 and v2. I think it looks good especially for a bolt on part. As far as downfalls what concerns me is that without a full underbody air will still follow on the topside of the diffuser and get stuck in our parachute rear bumpers. Im hoping RTheory can chime in on this part even though i know he has underbody plans in the works. The one other thing that could be a concern to me is ground clearance for loading on the trailer or a steep hill.
#16
I also know with 2-stroke pipes, the diffuser also needs to be an abrupt change. However temperature most likely is a factor here (related to compressibility).
I could purchase one and do some low-tech testing. However I have to think the market would be higher if the manufacturer did some low-tech testing as they have the product in hand. Unless of course it is simply an aesthetic device; but if that were the situation this site would suffer the same fate as clubroadster...
#19
You guys ask great questions.
For the people asking if the V3 is designed for function or for aesthetics, we designed it with function and form in mind. We are limited to what tools we have to test the diffuser but I do have access to CFD software. With my software we can't give you values such as how much downforce is created at what speed. Although we can illustrate how fluids would flow around a certain object(s). Admittedly our software is somewhat elementary in its CFD features since we only own the entry level of this particular 3D CAD/CFD software, but it does a good job of representing how the air should flow.
I did some CFD testing on the older V2 and this is what I came up with. Take it with a grain of salt, in our software we're limited to 50 plot lines. So I had to lower the ceiling of the test area to an unrealistic height just to increase the density of the plot lines under the car. So the curve of the air from under the car will be a little milder in real life, but either way it does show that the diffuser is creating a low pressure region under the car. I'll post some similar CFD analysis of the V3 once I get some bugs sorted in my software!
I also did a CFD analysis on the V1 and wrote a blog entry about it on the website. You can check it out here. September 19th, 2015 - Miata Rear Diffuser CFD Analysis ? R Theory Motorsports
And someone asked why run a diffuser with a curved profile instead of a flat inclined plane. Both styles work but curved profiles work much better. With a curved profile you get a more gradual change in flow and the air stays attached to the diffuser's surface much more effectively. With a flat inclined plane it's much easier for the air to stall. When I was playing around with different angles on the V1 with our CFD software the air started to stall around 11 degrees; and this was with a flat undertray under the rear subframe. Without the flat undertray it seemed to be only effective up to around 7 degrees. With the curved rear diffuser we can run more aggressive angles without the air stalling. Despite this we will still be offering the V1 since not everyone is after max downforce. This way we'll have a diffuser for different needs.
For the people asking if the V3 is designed for function or for aesthetics, we designed it with function and form in mind. We are limited to what tools we have to test the diffuser but I do have access to CFD software. With my software we can't give you values such as how much downforce is created at what speed. Although we can illustrate how fluids would flow around a certain object(s). Admittedly our software is somewhat elementary in its CFD features since we only own the entry level of this particular 3D CAD/CFD software, but it does a good job of representing how the air should flow.
I did some CFD testing on the older V2 and this is what I came up with. Take it with a grain of salt, in our software we're limited to 50 plot lines. So I had to lower the ceiling of the test area to an unrealistic height just to increase the density of the plot lines under the car. So the curve of the air from under the car will be a little milder in real life, but either way it does show that the diffuser is creating a low pressure region under the car. I'll post some similar CFD analysis of the V3 once I get some bugs sorted in my software!
I also did a CFD analysis on the V1 and wrote a blog entry about it on the website. You can check it out here. September 19th, 2015 - Miata Rear Diffuser CFD Analysis ? R Theory Motorsports
And someone asked why run a diffuser with a curved profile instead of a flat inclined plane. Both styles work but curved profiles work much better. With a curved profile you get a more gradual change in flow and the air stays attached to the diffuser's surface much more effectively. With a flat inclined plane it's much easier for the air to stall. When I was playing around with different angles on the V1 with our CFD software the air started to stall around 11 degrees; and this was with a flat undertray under the rear subframe. Without the flat undertray it seemed to be only effective up to around 7 degrees. With the curved rear diffuser we can run more aggressive angles without the air stalling. Despite this we will still be offering the V1 since not everyone is after max downforce. This way we'll have a diffuser for different needs.